Drug Information

Common brand names:

Summary of Interactions with Vitamins, Herbs, & Foods

Replenish Depleted Nutrients

Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K.1 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.2 The importance of this interaction is unknown.

Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin.3, 4, 5, 6, 7, 8, 9 Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.10, 11

Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K.23 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.24 The importance of this interaction is unknown.

Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin.25, 26, 27, 28, 29, 30, 31 Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.32, 33

Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K.45 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.46 The importance of this interaction is unknown.

Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K.49 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.50 The importance of this interaction is unknown.

Tetracycline can interfere with the activity of folic acid, potassium, and vitamin B2, vitamin B6, vitamin B12, vitamin C, and vitamin K.53 This is generally not a problem when taking tetracycline for two weeks or less. People taking tetracycline for longer than two weeks should ask their doctor about vitamin and mineral supplementation. Taking 500 mg vitamin C simultaneously with tetracycline was shown to increase blood levels of tetracycline in one study.54 The importance of this interaction is unknown.

Taking large amounts of niacinamide, a form of vitamin B3, can suppress inflammation in the body. According to numerous preliminary reports, niacinamide, given in combination with tetracycline or minocycline, may be effective against bullous pemphigoid, a benign, autoimmune blistering disease of the skin.57, 58, 59, 60, 61, 62, 63 Preliminary evidence also suggests a similar beneficial interaction may exist between tetracycline and niacinamide in the treatment of dermatitis herpetiformis.64, 65

Reduce Side Effects

The yeast Saccharomyces boulardii may help restore microbial balance in the intestines and prevent pseudomembranous colitis (PMC), an intestinal disorder caused by infection with Clostridium difficile. Even when Clostridium difficile is successfully treated with antibiotics, symptoms recur in about 20% of cases. Saccharomyces boulardii has been shown in controlled trials to reduce recurrences when given as an adjunct to antibiotic therapy.75, 76, 77

A common side effect of antibiotics is diarrhea, which may be caused by the elimination of beneficial bacteria normally found in the colon. Controlled studies have shown that taking probiotic microorganisms—such as Lactobacillus casei, Lactobacillus acidophilus, Bifidobacterium longum, or Saccharomyces boulardii—helps prevent antibiotic-induced diarrhea.81

The diarrhea experienced by some people who take antibiotics also might be due to an overgrowth of the bacterium Clostridium difficile, which causes a disease known as pseudomembranous colitis. Controlled studies have shown that supplementation with harmless yeast—such as Saccharomyces boulardii82 or Saccharomyces cerevisiae (baker’s or brewer’s yeast)83—helps prevent recurrence of this infection. In one study, taking 500 mg of Saccharomyces boulardii twice daily enhanced the effectiveness of the antibiotic vancomycin in preventing recurrent clostridium infection.84 Therefore, people taking antibiotics who later develop diarrhea might benefit from supplementing with saccharomyces organisms.

Treatment with antibiotics also commonly leads to an overgrowth of yeast (Candida albicans) in the vagina (candida vaginitis) and the intestines (sometimes referred to as “dysbiosis”). Controlled studies have shown that Lactobacillus acidophilus might prevent candida vaginitis.85

Potential Negative Interaction

Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera.99 Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients.100 Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera.103 Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients.104 Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

Berberine, a chemical extracted from goldenseal(Hydrastis canadensis),barberry(Berberis vulgaris), and Oregon grape(Berberis aquifolium), has been shown to have antibacterial activity. One double-blind study found that giving 100 mg of berberine at the same time as 500 mg of tetracycline four times daily led to a reduction of the efficacy of tetracycline in people with cholera.107 Berberine may have decreased the absorption of tetracycline in this study. Another double-blind trial did not find that berberine interfered with tetracycline in cholera patients.108 Until more studies are completed to clarify this issue, berberine-containing herbs should not be taken simultaneously with tetracycline.

Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet(Filipendula ulmaria), poplar (Populus tremuloides),willow(Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies.113 Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might.114 No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs.115 Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet(Filipendula ulmaria), poplar (Populus tremuloides),willow(Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies.119 Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might.120 No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs.121 Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet(Filipendula ulmaria), poplar (Populus tremuloides),willow(Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies.125 Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might.126 No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs.127 Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

Bismuth subsalicylate contains salicylates. Various herbs including meadowsweet(Filipendula ulmaria), poplar (Populus tremuloides),willow(Salix alba), and wintergreen (Gaultheria procumbens) contain salicylates as well. Though similar to aspirin, plant salicylates have been shown to have different actions in test tube studies.131 Furthermore, salicylates are poorly absorbed and likely do not build up to levels sufficient to cause negative interactions that aspirin might.132 No reports have been published of negative interactions between salicylate-containing plants and aspirin or aspirin-containing drugs.133 Therefore concerns about combining salicylate-containing herbs remain theoretical, and the risk of causing problems appears to be low.

Explanation Required

Milk thistle has been reported to protect the liver from harm caused by some prescription drugs.137 While milk thistle has not yet been studied directly for protecting people against the known potentially liver-damaging actions of metronidazole, it is often used for this purpose.

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.

Please read the disclaimer about the limitations of the information provided here. Do NOT rely solely on the information in this article. The Aisle7 knowledgebase does not contain every possible interaction.

The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2016.

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